System and method for determining the traceability of gemstones based on gemstone modeling

ABSTRACT

A method generating a more accurate 3D model for at least two gemstones using external surface of the gemstones; storing, in memory, the more accurate 3D model of the first gemstone and the second gemstone; comparing the more accurate 3D model of the first gemstone and the more accurate 3D model of the second gemstone from the stored memory; calculating, based on the comparison, a matching score for the more accurate 3D model of the first gemstone and the more accurate 3D model of the second gemstone, the matching score being informative of a match between the first gemstone and the second gemstone; and identifying the first gemstone and the second gemstone as being the same gemstone when the matching score meets a predefined matching criterion.

RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.16/907,265 filed 21 Jun. 2020, which is a continuation application ofU.S. application Ser. No. 16/220,690, filed Dec. 14, 2018, which is acontinuation application of U.S. application Ser. No. 14/653,679, filedJun. 18, 2015, now abandoned, which is a national stage application ofPCT Application No. PCT/IL2013/051041, filed Dec. 19, 2013, which claimspriority to Israel Application No. 223763, filed Dec. 20, 2012.

FIELD OF THE DISCLOSED SUBJECT MATTER

The disclosed subject matter pertains to using computer-aided 3Dmodeling to determine whether the 3D modeling in one gemstone is thesame as found in another gemstone. If the models match, or at least havea matching score, they are deemed to be one and the same gemstone. Thistechnique is useful in tracing the journey of a gemstone from the miningsite to the retailer of the finished/polished gemstone.

BACKGROUND OF THE DISCLOSED SUBJECT MATTER

It is known how important accurate 3D modeling of gemstones,particularly, diamonds, is for allowing diamond manufacturers,wholesalers and gemologists to evaluate the diamonds' proportions, itsdimensions as well as its symmetry, inter alia, for the purpose ofgrading the stones.

WO 99/61890 discloses a method and associated apparatus for measuring agemstone for its standardized grading. The system gauges the spectralresponse of a gemstone subject to a plurality of incident light sourceswithin an imaging apparatus. The operation of the imaging apparatus iscontrolled by an instruction set of a local station control dataprocessor.

U.S. Pat. No. 7,259,839 discloses a method of measuring a physicalcharacteristic of a facet of a diamond, in particular its edges, andobtaining a 3D model thereof including such edges.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

In accordance with one aspect of the presently disclosed subject matter,there is provided a computerized method for producing an accurate3D-Model of a gemstone comprising:

a) obtaining an original 3D-model of an external surface of saidgemstone, said surface including facets, edges abounding said facets,and junctions each constituting an area of meeting of at least threesaid edges associated with at least two facets;

b) imaging at least one selected junction of the gemstone with onlyportions of its associated facets and edges disposed adjacent thejunction, the location of said junction being determined based oninformation obtained at least partially by using the original 3D model,said imaging being performed under at least one imaging conditiondifferent from that at which the original 3-D model was obtained, andunder illumination conditions providing such contrast between adjacentfacets as allow to distinguish an edge therebetween;

c) analyzing by a computing device results of said imaging to obtaininformation regarding details of the gemstone at said junction; and

d) using by the computing device the information obtained in step c) forproducing an accurate 3D-model of said external surface of the gemstone,which is more accurate than the original 3-D model.

The above method of accurate 3D modeling a gemstone is particularlyadvantageous for modeling cut gemstones, such as for example, polishedand semi-polished diamonds, since it allows a much higher accuracy ofdetermination of cut and symmetry parameters of the stones than thatprovided by conventional 3D modeling techniques, by which the original3D model can be obtained.

In particular, the above method allows for determination of facetmisalignments and more accurate locations and geometry of junctions,compared with the original 3D model, revealing extra edges, facets andjunctions not revealed in the original 3D model, as well as superfluousedges, facets or junctions, which were erroneously recorded whenproducing the original 3D model; thereby the capability of performingfast, accurate and repeatable grading of the stones can be essentiallyimproved, allowing their more objective and more complete certificationand—not less importantly—replacing a manual observation by trainedgemologists.

Accurate 3D models obtained by the above method can also be used for anyother relevant purposes, such as for example: facilitating uniquefingerprinting of a stone for any relevant purpose requiring itsauthentication, and generating high-accuracy ray-traced virtual modelsthereof, which is particularly advantageous for trading diamonds viae-commerce, to provide higher confidence with regards to their actualappearance.

The method according to the presently disclosed subject matter cancomprise performing the steps (b) to (d) above for all junctionsrevealed in the original 3D model and also, in case the stone is a cutstone, for all non-revealed junctions existing in a predicted/plannedgeometry of the stone, but absent from said 3D model. Regarding theplanned geometry, it is the one, according to which it was supposed tobe cut. In connection with predicted/planned geometry, it is defined bya style used when shaping a diamond for its polishing, such as forexample, the brilliant cut. The cutting style does not refer to shape(pear, oval), but the symmetry, proportioning and polish of a diamond.The most popular diamond cutting style is the modern round brilliant,whose facet arrangements and proportions have been perfected by bothmathematical and empirical analysis. Also popular are the fancy cuts,which come in a variety of shapes—many of which were derived from theround brilliant.

The method can also reveal erroneously recorded junctions, i.e. thosethat were recorded in the original 3D model, but do not exist in thereal cut stone.

The method can also comprise obtaining a plurality of images of the oreach selected junction and selecting the plurality of images at leastone selected image, in which one or more edges seen therein aredistinguished over the remainder of the image better than in otherimages.

The method according to the presently disclosed subject matter can alsobe used to accurately determine the geometry of the stone's girdle andother girdle features such as naturals, extra facets and the like, andthereby generate a more complete accurate 3D model of the stone. In thisconnection, it should be explained that naturals are areas of theexternal surface of a cut stone, which have not been polished but ratherhave been left as they existed in the rough stone, from which the cutstone was shaped for polishing. Extra facets are those that have beencut/polished without them being a part of the planned geometry.

For this purpose, the method according to the presently disclosedsubject matter can comprise obtaining one or more images of as manyselected portions of the girdle as desired, said one or more imagesbeing taken under such conditions as to enable distinguishing at leastone planned feature at the or each said selected portion of the girdle;analyzing said one or more images to obtain information regardingdetails of the girdle at said selected portion thereof; and using saidinformation in generating said accurate 3D-model. The selected portionscan be chosen based on the original 3D model or based on any otherconsideration, and this can be done so that the whole girdle is imaged.

If the analysis of the images of the girdle results in the determinationof a new girdle feature, such as an extra facet and/or natural, saidinformation in step (h) can include information regarding at least onenew girdle feature absent from the planned girdle geometry; and saidpresenting in step (i) can include adding a representation of said atleast one new girdle feature to the girdle in the accurate 3D model ofthe stone. Said representation can be a graphical representation addedat the corresponding position on the girdle in the accurate 3D model ofthe stone, e.g. by drawing borderlines of the new feature, and evenadding thereto the graphical representation of its appearance as itappears in a corresponding image.

For example, the selection can be based on the determination orprediction of some new girdle feature absent from the original 3D modeland from planned girdle geometry, based on the information obtained fromthe analysis of said one or more images, subsequently identifying aportion of the girdle comprising said new girdle feature and performingfurther steps with respect to this portion of the girdle constitutingsaid selected portion.

The method according to the presently disclosed subject matter canfurther comprise predicting a new junction absent from the original 3Dmodel and from the planned geometry of the stone, based on theinformation obtained in the relevant steps described above; consideringsaid new junction to be a selected junction and performing above steps(b) to (d) with respect thereto. When a new edge is determined, which isabsent from the original 3D model, said predicting is performed byassociating said new junction with a predicted end of the new edge atits predicted intersection with an edge revealed in said original 3Dmodel.

When, based on the information obtained in the above-described method,it is realized that at least one revealed edge present in the 3D modelis missing from an image of its associated junction, such missing edgeis not included in the accurate 3D model generated by the method.

As mentioned above, the conditions at which the gemstone is imaged forgenerating its accurate 3D model are different from those, at whichimages of the gemstone are taken for generating its original 3D model.This difference can be, for example, in at least one of themagnification and resolution, which in the ‘accurate’ imaging is higherthan that, at which the original 3-D model was obtained; or in the depthof focus, which in the ‘accurate’ imaging can be lower than that, atwhich the original 3-D model was obtained.

In the above-described method, the following steps can be performed forgenerating the original 3D model of the gemstone (step (a) above):

-   -   illuminating the gemstone by means of one or more step-(a)        illumination device,    -   imaging the gemstone by means of a step-(a) imaging device, and    -   rotating the gemstone relative to the step-(a) illumination        device and step-(a) imaging device to obtain a plurality of        images, based on which said original 3D model is calculated.

For performing the ‘accurate imaging’ (in step (b) above), one or morestep-(b) illumination devices can be used to illuminate the gemstone,and different portions of the gemstone are imaged by means of a step-(b)imaging device, and wherein at least one of the following conditions isfulfilled:

-   -   at least one of said step-(b) illumination devices provides        illumination different from that of said step-(a) illumination        device, and    -   said step-(b) imaging device is different from said step-(a)        imaging device.

The gemstone can be illuminated by means of one or more step-(b)illumination devices with such an illumination that at least threeadjacent facets of the crown or the pavilion, or two facets of the crownor the pavilion and the girdle, are each at least partially illuminatedwith such a contrast between at least one couple of their adjacentilluminated surfaces as to enable distinguishing an edge therebetween.Such contrast can be obtained by at least one of the following:

-   -   said illumination being uniformly diffusive along the entire        field of vision of an imaging device used in step (b);    -   said illumination having a chief ray with an angle of incidence        selected based on an average between angles defined by said at        least three facets or two facets and the girdle, with said axis        Z;    -   said illumination being provided by an illumination source using        contrast improving techniques optionally comprising a mask        interacting differently with light exiting from said        illumination source at different surface portions of said mask,        including at least one of the following:    -   at least two surface portions with distinct absorption        properties,    -   at least two surface portions with different polarization        properties, and    -   at least two surface portions that provide different propagation        properties of the light.

The number of the above surface portions can correspond to the number offacets in the field of vision.

According to a further aspect of the presently disclosed subject matter,there is provided a device configured for producing an accurate 3D-Modelof a gemstone by the method described above.

In accordance with a still further aspect of the presently disclosedsubject matter, there is provided a computerized device forautomatically producing an accurate 3D-model of a gemstone, comprising

a 3D modeling device configured for obtaining an original 3D model of anexternal surface of a gemstone, including facets, edges abounding saidfacets, and junctions each constituting an area of meeting of at leastthree said edges associated with at least two facets;

an illumination and imaging device configured for imaging at least onejunction selected from the junctions in said 3D model, with onlyportions of its associated facets and edges disposed adjacent thejunction, under at least one imaging condition different from that atwhich the original 3D model was obtained, and under illuminationconditions providing such contrast between adjacent facets as to allowto distinguish an edge therebetween; and

a computing device configured to analyze results of said imaging toobtain information regarding details of the gemstone at said junctionand to use the obtained information for producing an accurate 3D-modelof said external surface of the gemstone, which is more accurate thanthe original 3-D model

In accordance with a still further aspect of the presently disclosedsubject matter, there is provided method of upgrading a first deviceconfigured for obtaining an original 3D model of an external surface ofa gemstone, in order to provide a second device for producing a moreaccurate 3D model of the external surface of said gemstone than theoriginal 3D model; said method comprising the steps of:

-   -   adding to said first device a second illumination device and a        second imaging device configured for imaging at least one        junction with only adjacent portions of its associated facets        and edges, the location of said junction being determined based        on information obtained at least from the original 3D model,        said imaging being performed with at least one imaging condition        being different from that or those at which the original 3-D        model was obtained, and under illumination conditions providing        such contrast between adjacent facets as allow to distinguish an        edge therebetween; and    -   adding computing capability for:    -   analyzing said images to obtain information regarding details of        the cut gemstone;    -   using said information for obtaining said more accurate 3D-model        of the external surface of the gemstone.

Said imaging condition can be at least one of the following:

-   -   a magnification higher than that provided by an imaging device        with which the original 3D image has been obtained;    -   a resolution higher than that provided by the imaging device        with which the original 3D image has been obtained; and    -   a depth of focus lower than that provided by the imaging device        with which the original 3D image has been obtained.

In accordance with a further aspect of the invention, there is provideda device

In accordance with a still further aspect of the present invention,there is provided a kit for upgrading a first device configured forobtaining an original 3D model of a gemstone, in order to obtain asecond device for producing a 3D model of said gemstone which is moreaccurate than the original 3D model, said first device comprising afirst set of gemstone holders each having a first gemstone mountingsurface, a first illumination source and a first imaging device, saidkit comprising at least the following:

-   -   at least one second illumination source different from the first        illumination device; and    -   a second imaging device different from the first imaging device.

The kit can further comprise a second set of gemstone holders eachhaving a second gemstone mounting surface and being configured formounting on a stage base such so as to allow an access of said secondillumination source to a space between said second gemstone mountingsurface and the stage base.

Alternatively, the kit can comprise means configured to use the firstset of gemstone holders in such a way as to allow an access ofillumination from said illumination source to a space below between saidfirst gemstone mounting surface.

The kit can further comprise a non-transitory computer readable storagemedium comprising computer readable program code embodied therein, thecomputer readable program code causing the device for accurate 3Dmodeling of gemstones to operate as detailed herein.

Additional possible features of different aspects of the presentlydisclosed subject matter are presented in the detailed description ofembodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosedherein and to exemplify how it may be carried out in practice,embodiments will now be described, by way of non-limiting example only,with reference to the accompanying drawings, in which:

FIG. 1A is a schematic perspective view of a device for producing anaccurate 3D-model of a gemstone, in accordance with one example of thepresently disclosed subject matter and is usable with the system of FIG.8;

FIG. 1B is a perspective view of a stage and the crown illuminationportion of the device shown in FIG. 1A;

FIG. 2A is a side view of the device shown in FIG. 1A, seen facing theX-axis;

FIG. 2B is a schematic partial side view of the device of FIG. 1a ,showing its pavilion illumination portion;

FIG. 2C is a schematic partial side view of the device of FIG. 1A,showing its crown illumination portion;

FIG. 2D is a schematic partial side view of the device of FIG. 1A,showing one example of its girdle illumination portion;

FIG. 2E is a schematic partial side view of the device of FIG. 1A,showing another example of its girdle illumination portion;

FIG. 3A-3C show a schematic view of different gemstone holders withgemstones of different sizes mounted thereon for producing theiraccurate 3D-models by the device shown in FIG. 1A;

FIG. 4 is a schematic view of a gemstone mounted on a support surface ofone of the holders shown in FIG. 3A-3C;

FIG. 5 is a schematic view of one example of a mask, which can be usedin one of the illumination portions of the device shown in FIG. 1A;

FIGS. 5A to 5C show a flow chart of a process according to one exampleof the currently disclosed subject matter;

FIGS. 6A and 6B and FIGS. 6C and 6D are schematic representations of twoexamples of portions of original and accurate 3D models of a gemstone,respectively, produced in the framework of a method according to oneexample of the presently disclosed subject matter;

FIG. 6E schematically illustrates an exemplary image of one surfaceportion of the gemstone obtained within the framework of a methodaccording to one example of the presently disclosed subject matter;

FIG. 7A to 7D schematically illustrate, in perspective and side views, aprocess of upgrading an original 3D modeling device (FIG. 7A, 7C) toobtain a device (FIG. 7B, 7D) for producing an accurate 3D-model of agemstone, in accordance with one example of the presently disclosedsubject matter.

FIG. 8 illustrates a system of gemstone tracing in accordance with thepresent invention.

DETAILED DESCRIPTION

FIG. 8 illustrates a system in accordance with the present invention fortracing the path or journey of a gemstone or gemstones from the placewhere they are mined to the retailor of the polished gemstone.

As is known, a gemstone's “journey” from the mining site to the retailermay take a number of steps, in which the gemstone may analyzed todetermine what the finished gemstone or gemstones derived from the roughstone will appear, using a device such as the Galaxy and Advisorsoftware made by the assignee of the present invention, SarineTechnologies. After having been examined, the gemstone may becut/cleaved into separate subparts, then polished to enhance appearance.

In FIG. 8, a rough, partially cut or fully cut gemstone 800 that has hada journey from the mine, the gemstone is placed inside the (or a like)device 802 according to FIG. 1A. The cut gemstone is then processed tocreate an accurate 3D model of an external surface. The images of theaccurate 3D model may then be stored in the cloud 804 for furtheranalysis.

When a gemstone 800′ which is presumed to be the same gemstone or atleast a part of the gemstone 800 arrives at the retailer or at anearlier stage, the gemstone 800′ may then be placed in a device 806,preferably one which is of the same type and design as the device 802.The gemstone 800′ is then processed to create an accurate 3D model of anexternal surface. The 3D model file of the gemstone 800 which had beenstored in the cloud 804 may then be downloaded into a computer 808 atthe retailer or wholesaler site and the image file derived from thedevice 806 compared with the image file from the gemstone 800 derivedfrom the device 802.

During the processing of the accurate 3D models of the gemstones 800there may not be a 1 to 1 identity of the gemstone 800 to the gemstone800′. However, it may be that some 3D model matches gemstone 800′. Ifthere are sufficient similarities in the inclusions in gemstone 800 andgemstone 800′, then the computer under suitable programming maydetermine a “score” to suggest whether the gemstones 800 and 800′ areone and the same gemstone. The comparisons of 3D models may be madebetween; partially cut and rough gemstones, cut and rough gemstones, cutand cut gemstones, rough and rough gemstones or any combination thereof.

One methodology that may be employed to “score” similarities may bederived from the disclosures in co-pending U.S. application Ser. No.17/235,015, filed Apr. 20, 2021 for SYSTEM AND METHOD OF UNIQUEIDENTIFYING A GEMSTONE, which application is assigned to the sameassignee as the present application and which application is hereinincorporated by reference in its entirety.

FIG. 1A schematically illustrates one example of a device 10 forproducing an accurate 3D model of an external surface of a gemstone Gcut in accordance with planned cut geometry to have a crown, a pavilion,a girdle and a table, the crown and the pavilion having planned facets,edges abounding the facets, and junctions, each constituting an area ofmeeting of at least three such edges associated with at least twofacets.

Whilst the gemstone's planned cut geometry is known, the gemstone's realgeometry and, particularly, the geometry of its pavilion, crown andgirdle is what the device 10 is aimed to determine with a high accuracy,by:

-   -   obtaining an original 3D-model of said gemstone,    -   imaging junctions with only adjacent portions of their        associated facets and edges, the junction's location being        determined based on information obtained at least partially by        using the original 3D model, with at least one of magnification        and resolution being higher and/or depth of focus being lower        than those at which the original 3-D model was obtained, and        under conditions providing such contrast between adjacent facets        as allow to distinguish an edge therebetween; and    -   analyzing results of the above imaging to obtain information        regarding details of the gemstone at said junctions; and using        this information for producing a new 3D-model of the gemstone        which is more accurate than the original 3-D model.

In the currently disclosed example, a brilliant-cut diamond isconsidered as the gemstone to be modeled, though this is a purelyexplanatory necessity, and there may be a number of possible gem cutgeometries that can be analyzed by the currently disclosed device. Infact, any cut of a gemstone can be modeled by the device, as long as itoffers one resting surface, on which the gemstone can be placed for theanalysis.

With reference to FIGS. 1A, 1B the device 10 comprises a stage station30 for supporting the gemstone G, a first 3D modeling device 60 with afirst optical axis FOA, for producing an original 3D model of thegemstone, and a second 3D modeling device 100 with a second optical axisSOA, for producing an accurate 3D model of the gemstone at an augmentedaccuracy level compared to that of the original 3D model.

The stage station 30 and the first and second 3D modeling devices areall fixedly mounted on a device base 12, with a device cavity 15 formedtherebetween, configured for receiving therein the gemstone G supportedat its resting or mounting surface S (see FIG. 4) by the stage station30 so as to allow to both 3-D modeling devices to have an optical accessto any surface of the gemstone except for its resting surface, withoutremoving the gemstone from the stage station.

The first and second 3D-modeling devices 60 and 100 are mounted on thebase 12 such that the spacial relationship of the first optical axis FOAto the base 12 remains constant, while the second optical axis SOA canmove during operations of the device, as described in further detailhereinbelow.

It has to be stressed, that the disposition of the second 3D modelingdevice 100 relative to the first 3D modeling device 60 as shown in thisexample is purely by way of a non-binding, explanatory exposition forthe purpose of understanding the herein disclosed subject matter, andthat any other relative disposition of the 3D modeling devices inrelation to each other is entirely possible.

The device 10 further comprises a computer device 300 comprising aprocessor (not shown) operatively coupled to a memory (not shown)storing appropriate software and a control card 310, which is soconnected to the above device's components on the one hand, and thecomputer device 300 by way of connection line 223 on the other, as toallow for necessary controlling all their operations.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specificationdiscussions utilizing terms such as “processing”, “computing”,“calculating”, “generating”, “configuring”, “controlling”, “choosing”,“building”, “deciding” or the like, refer to the action and/or processesof a computer that manipulate and/or transform data into other data,said data represented as physical, such as electronic, quantities and/orsaid data representing the physical objects. The term “computer” shouldbe expansively construed to cover any kind of electronic device withdata processing capabilities including, by way of non-limiting example,the computing device 300 disclosed in the present application.

The computerized operations in accordance with the teachings herein maybe performed by a computer specially constructed for the desiredpurposes or by a general-purpose computer specially configured for thedesired purpose by a computer program stored in a computer readablestorage medium.

Embodiments of the presently disclosed subject matter are not describedwith reference to any particular programming language. It will beappreciated that a variety of programming languages may be used toimplement the teachings of the presently disclosed subject matter asdescribed herein.

It is noted that the control card 310 can be integrated with thecomputer device 300. Additionally or alternatively, the functions of thecontrol card (or part of them) can be distributed between all or some ofthe components of the device 10.

The device's components will now be described separately in more detailwith reference to the corresponding drawings.

The Stage Station 30

With reference to FIGS. 1A and 1B, the stage station 30 comprises:

-   -   a replaceable gemstone holder 31; and    -   a stage base 42 with a drive stepper motor 43 so as to be        rotatable by the motor 43 about an axis of rotation RA.

The stage base 42 has a holder mounting surface 42 a, at which thegemstone holder 31 is mounted, disposed at a constant height relative tothe device base 12. The first optical axis FOA of the first 3-D modelingdevice 60 intersects with the axis of rotation RA at the origin of therelative Cartesian coordinate device RCCS of the device 10, the X-axiscoinciding with the FOA and the Z-axis coinciding with the RA.

The replaceable gemstone holder 31 comprises:

-   -   a holder base 32 with a holder base upper surface 32 a and a        holder base lower surface 32 b; and    -   a tower stage 36 integrally mounted on the holder base upper        surface 32 a with its one end and having at its other end a        gemstone supporting surface 37 configured for contacting the        resting surface S (best seen in FIG. 4) of the gemstone when        mounted thereon and defining an illumination plane IP (best seen        in FIG. 2B) parallel to the XY plane of the RCCS of the device        10. With reference to FIG. 2A, The X-Y plane of the RCCS        separates the space within the cavity 15 into a gemstone space        15 a disposed above, and a stage space 15 b disposed below, the        plane of the gemstone supporting surface, with respect to        vertical, gravity direction.

It should, however, be noted that such vertical orientation of the towerstage and the gemstone is not the only one possible. Any otherappropriate orientation can be used with corresponding specialarrangement for holding gemstones, as known in the art.

Reverting now to FIGS. 1A and 1B, the holder base lower surface 32 b isconfigured for detachable fitting thereof to the holder mounting surface42 a of the stage base 42 so as to lock the holder 31 to the stage base42 in a position that the tower stage 36 of the holder is coaxial withthe axis of rotation RA and the axis Z of the device 10.

The gemstone holder 31 is selected from a set of holders 31 a to 31 ncorresponding to several gemstone size groups A to N to be modeled withthe device 10. FIG. 3A-3C schematically illustrates three such gemstoneholders 31 a, 31 b, 31 c corresponding to three gemstone size groups A,B, C. Each size group is defined by a range of carat weights for whichthe corresponding holder size is suitable. Gemstones 1 _(A), 1 _(B), 1_(C) in FIG. 3A-3C each respectively represents a stone from one of therespective size groups A, B, C.

The main difference between the different holders 31 a to 31 n is in thegemstone support height SH, at which the gemstone supporting surface 37is located relative to the holder base lower surface 32 b, and which indifferent holders is, respectively, SHa to SHn so as to ensure that thelarger the size of a gemstone, the lower it is mounted relative to theholder base, i.e. the shorter the height SH. In other words, among theholders 31 a to 31 n, the holder with a maximal height SHmax isconfigured to support the smallest gemstones which the device 10 isconfigured to model. With the thickness of the holder base 32 (i.e. thedistance between its upper and lower surfaces 32 a and 32 b) being BH,the height of the tower stage 36 (i.e. the distance between the gemstonesupporting surface 37 and the upper surface of the holder base 32) beingTH, and the gemstone total support height being SH=TH+BH, the differencebetween different gemstone support heights SHa to SHn of differentgemstone holders is obtained in the described example by providing thecorresponding different heights BHa to BHn of the gemstone holders 32,and keeping constant the height TH of the tower stage 36.

In addition, the gemstone holders 31 a to 31 n differ in the area oftheir gemstone supporting surfaces 37, which is greater for the groupsof gemstones which have greater sizes, and which is such as to ensurethat any surface of the gemstone that is adjacent to its resting surfaceS but is other than the resting surface, protrudes radially from thegemstone supporting surface 37 when the gemstone is mounted thereon.Exemplary, each of the gemstones shown in FIGS. 3 and 4, is so mountedon the gemstone supporting surface 37 of the tower stage 36 that itsresting surface S is constituted by a central portion of its table GTwhilst the periphery of the table GTP and edges GTC of its intersectionwith the gemstone's crown C protrude radially from the gemstonesupporting surface 37.

It needs to be noted that, while the above-described configuration withseveral holders 31 n is one option for achieving the goal of placing thegemstone in the necessary position for analysis, other appropriatearrangements can be used. For example, instead of a plurality of holders31 n, there can be configured a tower stage 36 which is displaceablymounted within stage base 42, such that it can displace a gemstone alongthe Z-axis, and its support surface 37 can be either constant indiameter, or can be adjustable in its diameter.

As seen, in the present example the gemstone's resting surface is itstable. However, it should be understood that such orientation of thegemstone is not obligatory and it can be mounted in the device in anyother appropriate orientation. In addition, it should be understood thatthe orientation of the entire stage station or of its selectedcomponents including the gemstone supporting surface 37 can be otherthan that shown in the drawings.

The device 10 can further comprise a displaceable centering mechanism50, having a centering axis, which is configured for being:

-   -   placed in its operative, centering position in which it can        receive therein and center, on the gemstone supporting surface        37, the gemstone G so that the centering axis of the centering        portion coincides with the rotation axis RA and axis Z of the        device 10, and    -   subsequently displaced from its centering position to take its        inoperative position at a location spaced from the gemstone        supporting surface 37 and from the space between holder base 32        and the gemstone supporting surface 37.

The First 3D Modeling Device 60

The first 3D modeling device 60 can be of any known type configured forthe conventional computer calculation of a 3D model of the gemstone G,and it can be, for example, DiaMension™ device produced by SarinTechnologies Ltd., Israel, to which the description below particularlyrefers.

As shown in FIGS. 1A and 2A, the device 60 includes a backlightillumination unit 62 and an imaging portion 70 aligned along the firstoptical axis FOA, both mounted on the device base 12 on opposite sidesrelative to the gemstone supporting surface 37, so as to enable theimaging device 70 to scan the outer surface of the gemstone G whenmounted on the gemstone mounting surface 37 and rotated by the stagebase 42, and obtain thereby a plurality of electronic images of thesilhouettes of the gemstone surface in different angular positions ofthe gemstone relative to the axis Z, and to transfer the obtainedelectronic images via direct line 222 to the computer device 300configured to calculate the original 3D model of the gemstone.

The computer device 300 can be implemented as a separate devicecomponent operatively connected to other device components or can be, atleast partly, distributed over some or all of the device components. Thedetailed below functions of the computer device 300 can be implementedin any appropriate combination of software, firmware and hardware.

The optical axis FOA of the first modeling device 60 intersects the axisZ at the XY plane, spaced along the Z axis from the holder supportingsurface 42 a of the stage base 42, to a constant distance, which exceedsthe maximal support height SHmax. Due to this and due to the use of thegemstone holders 31 a to 31 n, which provide gemstones of differentsizes with different support heights SHa to SHn, it is ensured that anygemstone among those for the modeling of which the device 10 isdesigned, disposed on the gemstone supporting surface 37, will be fullyin the field of view FOV60 of the imaging device 70 during itsoperation.

The Second 3D Modeling Device 100

Reverting to FIG. 1A, the second 3D modeling device 100 comprises asecond illumination device generally designated as 110, and a secondimaging portion 200 configured for obtaining images of small areas onthe pavilion, crown or girdle of the gemstone G, with at least one of amagnification and resolution being higher, and/or depth of focus beinglower, than those provided by the first imaging portion 70. Examples ofsuch areas are shown in FIG. 4, illustrating a gemstone G mounted on atower stage 36, supported by the gemstone supporting surface 37 alongits resting surface S. The areas shown in FIG. 4 are areas P1 and P2 ofthe pavilion P of the gemstone, C1 and C2 of the crown of the gemstone,and G1 and G2 of the girdle GI of the gemstone.

As seen in FIG. 1A, the second illumination device comprises a pluralityof illumination sources 120, 160 and 190′ differently disposed relativeto the second imaging portion 200, which disposition is such as to allowthe illumination sources to direct their illumination to a space withinthe cavity 15 of the device 10, between the rotation axis RA and aproximal end 200′ of the second imaging portion 200 in order toilluminate at least areas of the pavilion, crown and girdle of thegemstone G, which are closest to the second imaging portion 200.

With reference to FIGS. 2B to 2E (illustrating different parts of thedevice 10 without the gemstone G), the second illumination device 110thus comprises:

a) a pavilion illumination portion 120 best illustrated in FIG. 2B,disposed in the gemstone space 15 a of the device cavity 15 above thegemstone supporting surface 37 so as to illuminate at least a portion121 of space between the rotation axis RA and the proximal end 200′ ofthe second imaging device 200, adjacent to the gemstone supportingsurface 37.

b) a crown illumination portion 160 best seen in FIGS. 1B and 2C, in theform of a light guiding body having a light exit surface 161, movablebetween an inoperative position thereof (not shown), in which it isspaced from the device cavity 15, and an operative position, in whichthe light exit surface 161 is disposed in the stage space 15 b of thedevice cavity 15 below the gemstone supporting surface 37, so as toilluminate at least a portion 121 of space between the gemstonesupporting surface 37 and the proximal end 200′ of the second imagingdevice 200, adjacent to the gemstone supporting surface 37; inparticular, when moving from its inoperative to its operative position,the light exit surface 161 of the crown illumination portion 160 is atleast partially brought into a region 123 between the gemstone holderbase 32 and the gemstone supporting surface 37, thereby ensuring thatthe light exit surface 161 is disposed at a constant distance D from thegemstone supporting surface 37 irrespective of the size of holder 31 orthe gemstone.

c) A girdle illumination portion, two different examples of which areshown in FIGS. 2D and 2E; the girdle illumination portion 190′ shown inFIG. 2D is disposed adjacent the proximal end 200′ of the second imagingportion 200 at a constant spacial relationship with the proximal end200′, so as to traverse at least a portion of the space 121 between therotation axis RA and the proximal end 200′ of the second imaging device200, and illuminate the gemstone space 15 a above and adjacent to thegemstone supporting surface 37, potentially from both the stage space 15b and the gemstone space 15 a; the girdle illumination portion 190″shown in FIG. 2E is disposed on the side of the gemstone supportingsurface 37 opposite the proximal end 200′ of the second imaging portion200, so as to illuminate at least the gemstone space 15 a above andadjacent the gemstone supporting surface 37.

The girdle illumination portion can be configured to provideillumination of any appropriate type, such as for example, diffusedillumination.

In order to increase contrast between adjacent facets of the pavilionand/or crown when imaged by the second imaging portion 200, any one ofthe pavilion and crown illumination portions can be configured toproduce a uniformly diffusive light beam, and can be so spaced from thegemstone supporting surface 37 along the rotation axis RA, so as toprovide a respective predetermined opening angle α_(p), α_(c) of itslight when incident on the illumination plane IP coincident with thesupport surface 37.

Referring now to FIG. 4 specifically, the opening angle α_(p), α_(c) isdetermined in correspondence with angles σ_(i) formed by normals N_(i)to facets that are adjacent to each other, which facets are expected tobe in the field of view P1 of the second imaging portion 200, withrespect to each other (see FIG. 4, N₁ and N₂; σ₁) and to the pavilion orcrown illumination axis PIA or CIA (see FIG. 4, ω_(p) for example),respectively. All these angles are known from the planned cut geometryof the gemstone and, thus, the value of the opening angle can beobtained empirically for stones of the same or similar planned cutgeometry. There can thus be provided a table presenting differentpositions of the pavilion/crown illumination portion per planned cutgeometry, and adjustment of such position can be performed manually bythe user or automatically.

Reverting to FIG. 2B, a pavilion illumination axis PIA is defined by thecentral normal of a light exit surface 122 of the portion 120, formingan acute angle γ with the rotation axis RA and intersecting the opticalaxis SOA at a location IL within the space 121 between the gemstonesupporting surface 37 and the proximal end 200′ of the second imagingportion 200. A crown illumination axis CIA, which is normal to the lightexiting surface 161, intersects the axis SOA at a location between thetower stage 36 and the distal end 200′ of the second imaging portion200.

In one specific example, the pavilion illumination portion 120 cancomprises a plurality of LEDs at one end thereof, with respective lensesand diffuser elements causing the light to exit from the portion 120 asdescribed hereinabove in a diffused light beam.

In addition, the pavilion illumination portion 120 can be provided witha contrast enhancing mask 140 disposed adjacent its light exit surface122, directed to provide a non-uniform illumination pattern in the space121, and thereby increase a contrast between adjacent facets. By way ofnon-limiting examples, such mask can have at least one of the following:

i. areas exhibiting distinct absorption properties;

ii. differently polarizing areas;

iii. areas providing different light propagation properties.

The number of areas in the above pattern can correspond to the number offacets expected to be in the field of vision of the imaging portion 200.

One example of the mask 140 designed in accordance with option (i) aboveis to shown in FIG. 5, in which segments 140 a and 140 b are configuredto fully absorb, and segments 140 c and 140 d are configured to fullytransmit, light exiting from the pavilion illumination source 140.

In the described device, by way of non-limiting example only, the crownillumination portion is in the form of a light guide 170 with a proximalend 175 configured for receiving a light source, such as a LED 174, sothat it emits light within the light guide, a distal end 177 configuredfor emitting light reaching the distal end toward the portion 121 of thespace located between the gemstone supporting surface 37 and theproximal end 200′ of the second imaging device 200, and an intermediateportion 176 therebetween via which the light emitted from the lightsource propagates by multiple reflection thereof from the light guidesurfaces 172, which can be provided with a reflective coating. Thedistal end 177 of the light guide can be provided with means, such as adiffusive coating or plate 161 configured to uniformly diffuse lightexiting therefrom.

The crown illumination portion can also be enhanced by masking the lightexit surface 161 according to the same principles and details describedabove for the pavilion illumination portion 120.

It is furthermore clear to the skilled person, that the above describedlight guide 170 of the crown illumination portion 160 is only onespecific, non-binding example of numerous strategies for illuminating agemstone mounted on stage 31 from below.

There are many other ways of achieving the same goal, for example,amongst others, by placing an OLED at the location of light exitingsurface 161, or concentrating the light of more than one LED by a singlelight guide of a different form, or using fiber optics, only to namethree more examples.

If desired, the illumination portions can be provided with degrees offreedom required to obtain their desired position and effect. As shownin FIG. 1A, in the described example, the degrees of freedom for thepavilion illumination portion 120 can be provided by the possibility ofmoving the same in at least one of the following manners: translationalong a first axis K1 parallel to the Z-direction, rotation about asecond axis K2 that is perpendicular to a plane passing through the Zaxis and the second optical axis SOA, and translation along a third axisK3 parallel to axis Y.

The computer device 300 can control respective portions of the devicevia control card 310. In the described example, this concerns allportions except for the electronic imaging portions, as describedfurther and hereinabove, which in the described example is connected tothe computer device 300 by direct communication lines 222. However, thisdoes not need to be the case and should be seen as optional.

The second imaging device 200 will now be described in more detail, withreference to FIG. 1 a.

The second imaging portion 200 comprises an optical device 220 and anelectronic imaging portion 240 (not seen), both mounted within a housing226, and a mechanical positioning arrangement 270 for supporting thehousing 226 and moving it as required.

The optical device 220 can be a telecentric optical device providing thesame magnification X at all distances therefrom. Optionally, there canbe mounted an iris or other portion for adjusting the depth of focus andthe resolution of the device, either manually or automated.

The second imaging portion 200 is configured to provide images formed bythe optical device 220 and recorded by the electronic imaging portion240, with depth of focus and a resolution optimized to distinguish edgesof a gemstone along a distance L which is not shorter than the length ofthe smallest planned edge of the smallest stone to be measured by thedevice and, optionally, not greater than a fraction of the maximaldimension of such smallest stone. The optimization of depth of focus andresolution, with the resultant magnification, is aimed at attainingimages of small areas of the gemstone, such as for example, the areas ofjunctions of the gemstone including only parts of the associated facetsthat are adjacent thereto, with a quality sufficient for distinguishingdetails of said areas such as intersections between the imaged facets'parts, along the required distance, and it will ultimately result inthat at least one of the magnification and resolution being higher,and/or depth of focus being lower, than that provided by the firstimaging device when obtaining the original 3-D model.

The second imaging device 200 can further comprise image enhancingportions in the form of filters or polarizers 201 placed in front of theoptical device 220, and thereby contrast of the images can be enhanced,or normally invisible structural effects can be made visible, if needed,thereby further enhancing the abilities of the device to accuratelydistinguish particulars needed for describing the gemstone.

The electronic imaging portion 240 is in the form of a CCD camera whichreceives on its sensing pixels a magnified image formed by the opticaldevice 220 and produces electronic images to be communicated via directline 222 to the computer device 300.

The positioning arrangement 270 is configured to support the housing 226with the optical device 220 and the electronic imaging portion 240, andto provide translation thereof along an axis I₁ parallel to and spacedfrom rotation axis RA along a direction parallel or coinciding with thesecond optical axis SOA, as well as translation along the second opticalaxis SOA, and optionally to provide for rotational displacement aroundan axis I₂ perpendicular to the rotation axis RA and the SOA, as well asa translation along axis I₂. To this end, the positional arrangement 270is connected to suitable step motors (not shown) that are controlled viacontrol card 310 and communication line 223 by the computer device 300.

The computer device 300 is configured to control the operation of thestage station and the illumination and imaging devices, to execute imageprocessing analyses and 3D computations necessary for performingcorresponding computational steps described hereinbelow, and to providea graphic user interface for human/machine interaction for controllingthe whole 3D modeling process, and capable of presenting 3D models tothe user.

In operation, the stage 30 rotates the mounted gemstone 1 such as tobring its side at which a surface portion to be imaged is disposed infront of the second imaging device 200; the mechanical positioningarrangement 270 moves the second imaging device 200, as required tobring the surface portion to be imaged into the field of view FOV of thesecond imaging device and at such distance from the second imagingdevice as to ensure that the optical device 220 is focused on thesurface portion to be imaged.

The device 10 can further comprise a cover (not shown) to cover thecavity 15 thereof from outside influence at least during operation ofthe device.

The above device 10 can be built as a completely new device or can beproduced as an upgrade of an existing device configured for producing aconventional 3D model of a gemstone, which includes a conventional stageand a conventional 3D modeling device.

With reference to FIGS. 7A to 7D, the following are the steps that canbe performed in accordance with one example of such upgrading of anexisting 3D modeling device 620, which can be Sarin's DiaMension™, withan existing stage 610, existing stage base 611, existing machine base612, motor 615, computer device 300 configured in an existing manner,and existing control card 628:

-   -   the existing stage 610 with its existing stage base 611 is        disassembled in its entirety from the existing machine base 612;    -   the motor 615 mounted in the existing device at position M1, at        height MH1 from the Y-axis, is re-mounted at a lower position,        at height MH2;    -   a new stage, which is built according to all the features and        functionalities as described hereinabove for stage 30, is        mounted in the same location instead of the existing stage 610,        with the main difference that the stage base 42 is laid lower        than the existing stage base 611 of the stage 610 by a height A;    -   referring now to FIG. 7B, an illumination device 710, with all        features and details according to the illumination device 110,        and an imaging portion 720 with all features and details        according to the imaging device 200, are installed in the        corresponding locations as described above, to form the second        3D modeling device;    -   a new driver card 750 for the device is supplied and connected;        and    -   the computer device 300 is provided with a capability for        controlling the device and providing necessary computations as        described below.

Finally, a new cover is mounted to reversibly cover the mounting cavitywith all its illumination portions 15 from outside influence at leastduring operation of the device.

Operation of the Device 10

Whether built as a completely new device or as an upgrade of an existingdevice, the operation of the device 10 for producing an accurate 3Dmodel of the gemstone G can comprise all or a part of the stepsdescribed below, with reference to block-diagrams 5A to 5C, depending ondesired scope of examination of a gemstone.

Stage I: Gemstone Mounting and Device Preparation

In step 1000, a size group (for example group B) for a gemstone 1 (forexample gemstone 1 b) to be examined is chosen among the groups ofgemstones with which the device 10 is planned to operate (see FIG. 3A-3Cand corresponding explanations above).

Step 1001, it is ensured that the gemstone holder 31 of a correspondingsize (in this case the gemstone holder 31 b) is mounted on the stagebase 42 and a lens is mounted in the imaging portion 70 selectedaccording the size group of the stone.

During mounting of the gemstone holder 31, if required, the crownillumination device 160 is in its inoperative position, after which itis brought back to its operative position.

In step 1002, the stone is thoroughly cleaned and mounted on thegemstone holder 31, which in turn is mounted on the stage base 42, asdescribed in detail hereinabove.

In step 1003, if a centering mechanism is used, it is utilized now, andthen removed from the stage so as not to interfere with the operation.

If the portion allows adjustment of the position of any of the pavilion,crown and girdle illumination portions by a user, this should be done ina next step (not included in FIG. 5A).

Upon activation of the device 10 by means of the respective command inthe GUI 350, the device operates automatically as described below undercontrol of the computer device 300.

Stage II: Scanning the Gemstone by the First 3D Modeling Device 60 toProvide an Original 3D Model Thereof

In step 1004, the first 3D-modeling device 60 is activated, the stagebase 42 with the gemstone holder 31 and the gemstone is caused to rotateby predetermined amounts, the backlight illumination unit 62 illuminatesthe gemstone, and for each incremental rotation, an image of thesilhouette of the gemstone against the bright backlight is formed andrecorded by the first imaging portion 70, until the gemstone has beenrotated 360 degrees (alternatively the rotation of 180 degrees can beused where this is sufficient to obtain all necessary silhouettes of thestone).

In step 1005, upon completion of the process of obtaining silhouetteimages, the computer device 300 extracts 3D-relative coordinates of theimaged gemstone from the images by edge recognition techniques, andcalculates the original 3D model 400 based on the extracted data, whichincludes inter alia a plurality N of revealed junctions and edges.

Stage III: Obtaining a More Accurate 3D Model of the Gemstone by theSecond 3D Modeling Device 100

Sub-Stage III.1: Distinguishing Edges and Junctions

Without moving the stone relative to the supporting surface 37, in thenext step 1006, the second 3D modeling device 100 chooses a selectedjunction N1 amongst the revealed junctions found by the computer device300.

In step 1007, the computer device 300 provides instructions to activateat least one of the three illumination portions, according to thelocation of the selected junction N1: if the selected junction N1 islocated on the pavilion, the pavilion illumination device 120 isactivated, if the junction N1 is located on the crown, the crownillumination device 160 is activated. At any time during operation, atleast one, suitable illumination portion is active. Sometimes it can beadvantageous to operate two illumination portions; for example bothpavilion and crown illumination portions can be used when junctions atthe merger of the crown and table of the stone need to be imaged.

The device in step 1008 rotates the gemstone holder 31 and moves theimaging device 200 by means of the above described features to bring theselected junction N1 within the field of view FOV of the imaging deviceand to focus the imaging device on the junction N1.

In step 1009 an i number of images of the junction N1 is taken, underdifferent lighting conditions LN1, with i>1. The lighting conditions LN1are produced by a slight rotation of the gemstone 1 b relative to thesecond 3D modeling device per increment, such that the selected junctionN1 remains in the FOV of the imaging device, but under changed angles ofits facets relative to the respectively operative illumination deviceand imaging device, thereby changing the light pattern reflected by thefacets of gemstone 1 b towards the imaging device 200, and producingdifferent contrasts between the facets.

In step 1010, the computer device 300 compares the i images of thejunction N1, and selects the best image with contrasts best suited forfurther processing (in the steps 1011-1025 below)

Referring now in particular to FIG. 6E, in step 1011, the computerdevice 300 determines particulars such as all detectable edges DE basedon the selected image and establishes their coordinates:

-   -   For facets F1 and F2, the computer device 300 distinguishes a        difference D12 in pixel color or brightness value at their        mutual border MB12. The location where this difference D12 is        largest is then defined as detected edge DE12.    -   Likewise, based on all facets F1 to F4, all other detected edges        DE23, DE34, DE14 and DE24 are defined, and their coordinates are        recorded, for further processing;    -   If in step 1011 no edges are visible, then step 1011 a is        performed.

If in step 1011 edges are visible, then step 1012 is performed.

In step 1012, the computer device 300 determines discrepancies betweenthe number of edges NE detected in the selected image and the number ofedges NER revealed in the junction N1 of the original 3D model. IfNE>NER, there are new edges present in the selected image, and this isthus recorded in a list of images with new edges for later processing.

If NE<NER, there are edges missing in the image, and subsequently, step1011 a is performed.

In step 1011 a, the computer device 300 associates all edges in theselected image with edges present in the original 3D model. Thus, if thenumber of revealed edges in the original 3D model at the regioncorresponding to that shown in the selected image, is greater than thenumber of edges found in the image, the superfluous edges present in theoriginal 3D model, but missing from the image, are subtracted, andeventual adjacent facets are merged.

In step 1013, the computer device stores results of the previous stepsin its memory or in another suitable non-transitory computer readablemedium.

In step 1014, the computer device 300 checks for the revealed junctionsthat have not yet been processed. If there are such junctions left, thecomputer device moves to the next junction in its list, and jumps backto step 1007.

This loop is executed, until there are no revealed junctions left.

Once all the revealed junctions have been examined, and referring now toFIG. 5B, in step 1014 a, the computer device compares the number ofjunctions NJ in the planned geometry to the number of revealed junctionsNJR in the original 3D model, and if NJ>NJR, again, there arenon-revealed junctions. The computer device records coordinates of thesenon-revealed junctions in a list for non-revealed junctions NoJR.

In step 1015 the computer device chooses between the two lists NER andNoJR as follows:

-   -   the device checks first, if the list NER contains items, and if        in the affirmative, it chooses this list and enters sub-stage        III.2. If the list NER is empty, the device then moves to the        list NoJR, and enters sub-stage III.3. If the list NoJR is        empty, the device moves to step 1110 and starts sub-stage III.4,        the girdle analysis, if a girdle is to be found.

If no girdle is to be found, the computer device moves to step 1200, andbuilds

Sub-Stage III.2: Determining New Junctions Based on New Edges

In step 1017, the computer device has determined new edges byassociating each edge in the image with a revealed edge in the original3D model. Since, for all images in this list NER, by definition thereare more edges than revealed edges, at the end of this process there arenew edges disclosed. The computer device records all new edges of everyselected image with their coordinates.

Since the coordinates of all new edges of every selected image have beenrecorded, the coordinates of their projections away from the junctionfound in the image can now be calculated and a potential junction areais determined where this extension is expected to meet with a respectiverevealed edge of the original 3D model. The coordinates for hispotential junction area are recorded by the computer device.

The manner in which new edges and new junctions are associated to theoriginal 3D model is described at the end of this description, in moredetail with reference to FIGS. 6A to 6D.

For each potential junction area, step 1018 is performed by the computerdevice 300, by listing the potential junction as a revealed junction,and the respective image is removed from the list NER; as long as thereare still items in the list NER, the computer device then jumps back tostep 1017.

If there are no new items in the list NER, i.e. NER is empty, thecomputer device performs step 1020 by jumping back to step 1007 andperforming the sub-stage III.1 of steps 1007 to 1014, with eachpotential junction area now recorded as revealed junction.

Upon reaching step 1015, with an empty list of NER, the computer devicewill now either find items in the list NJR and process with thesub-stage III.3 described below, or it will find both lists empty.

Sub-Stage III.3: Determining New Junctions Based on the Planned Geometry

If there are items in NoJR, the computer device performs step 1122 bynumbering the non-revealed junctions, and the computer device chooses apotential new junction NoJ1.

In step 1123, the computer device provides instructions for focusing theimaging device on the location for the potential new junction NoJ1.

In step 1124, if a new junction is found, the location is recorded asrevealed junction. If no junction is to be found, the computer deviceperforms step 1011 a and follows the subsequent routine back to step1015, where it will again find items in the list NoJR, and continue inthe routine of steps 1122-1124.

If a new junction is found, the computer device performs step 1125 bydeciding if this was the last potential new junction. If not, thecomputer device jumps to step 1123. If in the affirmative, the computerdevice performs step 1126 and returns to sub-stage III.1, steps1007-1014, and again repeats this loop until there are no revealedjunctions left in the list.

In step 1026, the computer device decides whether to progress to step1110 (FIG. 5C)—to the girdle analysis process—or to forego girdleanalysis and progress to step 1200. This decision can be made based onhuman intervention or automatically upon finding of a girdle.

Stage IV: Building an Accurate 3D Model

In step 1200, the computer device builds an accurate 3D model of thegemstone based on all saved results.

Optional Sub-Stage III.4: Girdle Analysis

In step 1026, the computer device progresses to step 1110 (FIG. 5B)—tothe girdle analysis process.

In step 1110, the computer device provides instructions for girdleillumination activation, and for shutting-off all other illuminations.

In step 1111, the girdle is scanned by capturing a plurality of imagesof different sections thereof. This scanning process is performed suchthat the whole girdle is imaged by the respective imaging device.

In step 1112, the images are analyzed by the computer device 300, andall distinguishable particulars are recorded. These particulars are usedby the computer device in step 1113 to determine new girdle featuresabsent from the planned girdle geometry, such as for example extrafacets and/naturals.

The computer device thus first identifies the region where a new girdlefeature is located, which can be at a location adjacent the place, wherea junction is missing that was supposed exist, according to the plannedpavilion/crown geometry, or where in the images taken in step 1111,there is a distortion in the girdle pattern relative to the one planned.

The computer device then defines borderlines of the above region, itsshape and area and the new girdle feature is classified. For example, ifthe borderlines are straight lines, the new girdle feature is an extrafacet, which is a planar surface. If the borderlines are not straightand clearly defined, this would be typical of a natural. Thus, in step1114 the computing device makes a decision on the manner, in which eachnew girdle feature is to be represented in the accurate 3D model, andthe corresponding information is stored.

Stage IV′: Building an Accurate 3D Model with Girdle Information

In case the sub-stage III.4 is performed, in step 1200 described above,the accurate 3D model of the gemstone can be complemented with girdleinformation obtained therein, based on images of differentsections/particulars of the girdle and/or there description. Thisinformation can be in the form of the graphical representation of newgirdle features, such as extra facets and/or naturals, added at thecorresponding position on the girdle in the accurate 3D model of thestone, e.g. by drawing and presenting by the computer device borderlinesof the new feature, and even adding thereto its graphical representationof its appearance as it appears in a corresponding image. The computerdevice can also knit the images of different sections of the girdletogether to form a developed view of the whole girdle.

Associating, by the computer device. new edges and new junctions to theoriginal 3D model, referred to in sub-stage III.2 described above, willnow be described with reference to FIG. 6A-6D, illustrating the way inwhich the computer device, based on the data described hereinabove,associates new edges and new junctions to the 3D model.

In a first case, where only a facet is missing but two revealedjunctions PA1 a, PA1 b connected by the edge exist and are known, thecomputer device, upon examining junction PA1 a, will detect that the newedge NE is supposed to connect to a second revealed junction PA1 b andwill verify at this second revealed junction PA1 b if there is a missingedge NE′ there, too, to verify the missing facet. If it didn't detectthe missing edge at the second revealed junction PA1 b, it will needanother set of images along the detected edge to detect where this edgeis connected to.

In a second case, where there is a missing junction, this means that afacet is missing and also the junction PA3 where the edge supposed toconnect to is unknown. The computer device will calculate where theprojection PNE2 of edge NE2, originating at the revealed junction PA2 issupposed to be connected to, and it will find that there is no knownjunction in that direction. The edge will then join with anotherrevealed edge RE and that will be a suspicious position for the missingjunction PA3. The computer device will need another set of images ofthis suspicious area at the suspicious position PA3 to verify if thepartial edge NE2′, which is the end point of the projection from NE2, isreally forming a junction there.

It should be noted that though in the above exemplary description ofoperation of the device, the analysis of the gemstone is performed forall its non-planar parts, namely, pavilion, crown and girdle, this doesnot necessarily need to be the case. Depending on the purpose of theanalysis, only one part of a gemstone can be accurately modeled, e.g.when only one part of a rough stone has been cut to have a planned cutgeometry.

Moreover, a device according to presently disclosed subject matter canbe used for obtaining images of a gemstone for any desired purpose, withor without focusing on any particular locations and analyzing imagesthereof to find features not revealed by the method described above.

1. A computerized method comprising: (a) capturing a plurality of imagesof the external surface of a first gemstone having a planned geometry,the external surface including facets, edges abounding said facets, andjunctions each constituting an area of meeting of at least three saidedges associated with at least two facets, and using the plurality ofimages for generating an original 3D-model of the external surface ofsaid gemstone comprising revealed edges and revealed junctions, and (i)considering one or more of the revealed junctions to be selectedjunctions; and (ii) determining at least one non-revealed junction, ifexisting in said planned geometry but absent from said original 3Dmodel, and considering a planned location of said non-revealed junctionto be the selected junction; (b) using the original 3D model to obtaininformation, based on which location of the selected junctions isdetermined, and subsequently imaging selected junction areas of eachsuch selected junction with only portions of its associated facets andedges disposed adjacent this junction, said imaging being performedunder illumination conditions different from those, at which saidplurality of images were taken and providing such contrast betweenadjacent facets as to allow to distinguish an edge therebetween; (c)analyzing results of the imaging selected junctions to obtain a firstset of information regarding the selected junction areas; (d) using thefirst set of information for producing an improved 3D-model of saidexternal surface of the first gemstone, which is more accurate than theoriginal 3D model creating a more accurate 3D model of the firstgemstone; (e) storing, in memory, the more accurate 3D model of thefirst gemstone; (f) analyzing a second gemstone using the method of (a)through (d); (g) storing, in memory, the more accurate 3D model of thesecond gemstone; (h) comparing the more accurate 3D model of the firstgemstone and the more accurate 3D model of the second gemstone from thestored memory; (i) calculating, based on the comparison, a matchingscore for the more accurate 3D model of the first gemstone and the moreaccurate 3D model of the second gemstone, the matching score beinginformative of a match between the first gemstone and the secondgemstone; and (j) identifying the first gemstone and the second gemstoneas being the same gemstone when the matching score meets a predefinedmatching criterion.